Electro-hydraulic actuators are generally known. A typical electro-hydraulic actuator includes an electric motor that drives a hydraulic pump to move fluid from a reservoir to a hydraulic actuator for actuating the actuator. When the electric motor is driven in a first rotational direction, the hydraulic fluid moved by the hydraulic pump extends a rod of the actuator. When the electric motor is driven in a second rotational direction, opposite the first rotational direction, the hydraulic fluid moved by the hydraulic pump retracts the rod of the actuator.
The components of an electro-hydraulic actuator are supported in a housing. The housings of many known electro-hydraulic actuators include a first portion for the actuator and a second portion, connected to the first portion, for the electric motor, hydraulic pump, and reservoir. Fluid passages are formed in the housing such that a complete hydraulic circuit is contained within the housing.
Electro-hydraulic actuators commonly are used for moving items between first and second positions. In one example, an electro-hydraulic actuator may be used to move a motor for a motor boat between trim positions. In another example, the electro-hydraulic actuator may be used to move a door, such as an armored door that is difficult to move manually. In the event of a power loss or other event that results in a failure of motion of the actuator of the electro-hydraulic actuator, a manual release for enabling manual movement of the actuator (or item attached to the actuator) is desired.